1,330 research outputs found

    The conjecture concerning time variations in the solar neutrino flux

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    The results of the Fourier transformation of the unequally-spaced time series of the recorded Ar-37 production rate of the solar neutrino experiment (runs 18 to 80, 1970 to 1983) are reviewed. Significance criteria for every period discovered by the harmonic analysis are determined. A Fourier synthesis of certain discovered harmonics are performed. It seems that the solar neutrino flux increases shock-like with a period of approximately 8.3 years and after that breaks down. Possible connections between the periods found by the harmonic analysis and several observed phenomena on the solar surface are indicated

    Start to end simulations of the ERL prototype at Daresbury Laboratory

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    Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will serve as a research and development facility for the study of beam dynamics and accelerator technology important to the design and construction of the proposed 4th Generation Light Source (4GLS) project. Two major objectives of the ERLP are the demonstration of energy recovery and of energy recovery from a beam disrupted by an FEL interaction as supplied by an infrared oscillator system. In this paper we present start-to-end simulations of the ERLP including such an FEL interaction. The beam dynamics in the highbrightness injector, which consists of a DC photocathode Gun and a superconducting booster, have been modelled using the particle tracking code ASTRA. After the booster the particles have been tracked with the code elegant. The 3D code GENESIS 1.3 was used to model the FEL interaction with the electron beam at 35 MeV. A brief summary of impedance and wakefield calculations for the whole machine is also given

    Electron beam profile imaging in the presence of coherent optical radiation effects

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    High-brightness electron beams with low energy spread at existing and future x-ray free-electron lasers are affected by various collective beam self-interactions and microbunching instabilities. The corresponding coherent optical radiation effects, e.g., coherent optical transition radiation, render electron beam profile imaging impossible and become a serious issue for all kinds of electron beam diagnostics using imaging screens. Furthermore, coherent optical radiation effects can also be related to intrinsically ultrashort electron bunches or the existence of ultrashort spikes inside the electron bunches. In this paper, we discuss methods to suppress coherent optical radiation effects both by electron beam profile imaging in dispersive beamlines and by using scintillation imaging screens in combination with separation techniques. The suppression of coherent optical emission in dispersive beamlines is shown by analytical calculations, numerical simulations, and measurements. Transverse and longitudinal electron beam profile measurements in the presence of coherent optical radiation effects in non-dispersive beamlines are demonstrated by applying a temporal separation technique.Comment: 12 pages, 11 figures, submitted to Phys. Rev. ST Accel. Beam

    Time resolved phase space tomography at flash using a transverse deflecting RF-structure

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    Skin tests, T cell responses and self-reported symptoms in children with allergic rhinitis and asthma due to house dust mite allergy

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    Abstract BACKGROUND: In allergic responses, a distinction is made between an early-phase response, several minutes after allergen exposure, and a late-phase response after several hours. During the late phase, eosinophils and T cells infiltrate the mucosa and play an important role in inflammation. OBJECTIVE: The aim of this study was to examine the relationship between allergen-induced late-phase skin responses and in vitro T cel

    Die Teilnahme der Arbeiterjugend am sozialistischen Wettbewerb: Parlamentsstudie 1975 ; Teilbericht II.2

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    Die Studie, basierend auf einer schriftlichen Befragung von ca. 7400 jungen WerktĂ€tigen in der DDR im FrĂŒhjahr 1975, dient der ideologisch-theoretischen Vorbereitung des 10. Parlaments der FDJ. Ihr Ziel besteht in der Analyse der Ergebnisse der sozialistischen Jugendpolitik auf der Grundlage der BeschlĂŒsse des 8. Parteitags des SED, insbesondere bei der Entwicklung des sozialistischen Klassenbewußtseins der Jugend, in der Bestimmung der fĂŒr diese Entwicklung wichtigen Prozesse sowie in der Erarbeitung von Empfehlungen fĂŒr die vom 10. Parlament der FDJ zu beschließenden Dokumente zur kommunistischen Erziehung der Jugend. Die Teilnahme der Arbeiterjugend am sozialistischen Wettbewerb wird auf drei Ebenen untersucht: (1) Einsatz der werktĂ€tigen Jugend fĂŒr volle Ausnutzung der Arbeitszeit, hohe QualitĂ€t der Arbeit und sparsamen Umgang mit Material und Energie; (2) Teilnahme der Arbeiterjugend an volkswirtschaftlichen Initiativen und an der Qualifizierung; (3) Informiertheit der Arbeiterjugend ĂŒber grundlegende ökonomische Sachverhalte und Zielstellungen. (ICE

    Effect of Fluticasone propionate Aqueous Nasal Spray Treatment on Platelet Activating Factor and Eicosanoid Production By nasal Mucosa in Patients with A house Dust Mite Allergy

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    The relationship between the release of platelet activating factor (PAF), leukotriene C4/D4/EE (LTC4/D4/E4) and prostaglandin D2 (PGD2) from nasal mucosa in vivo was examined in 24 rhinitis patients allergic to the house dust mite (HDM). During a double blind placebo controlled cross-over study 200 ÎŒg fluticasone propionate aqueous nasal spray (FPANS) was administered twice daily for two weeks. In response to allergen provocation (100, 1 000, 10 000 Bu/ml) and during the 9.5 h after this challenge the nasal fluid was obtained by washing the nose with saline and the levels of PAF, LTC4/D4/E4 and PGD2, as indicators of mediator release, were measured at the following time-points: baseline (t = − 1/2), allergen provocation with 10 000 Bu/ml (t = 0), 3.5 and 7.5 h (late phase). After allergen provocation the levels of the mediators increased in the nasal fluids of placebo treated patients (x-fold increase to baseline: PAF, 15; LTC4/D4/E4, 12; PGD2, 1.5). In fluids of patients treated with FPANS these levels tended to decrease. At the time of provocation the levels of PAF, LTC4/D4/E4 and PGD2 showed a significant correlation. The results indicate that these mediators can be used as markers of allergic reactions against house dust mites and that fluticasone propionate aqueous nasal spray tended to reduce the release of mediators of inflammation correlated with beneficial effects on clinical symptoms in this type of allergic reactions

    Occupational allergy in Strawberry Greenhouse workers

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    Background: Employees in strawberry greenhouses are highly exposed to several (potential) allergenic agents. However, no occupational allergy in this branch has been described before. First, the presence of work-related allergic symptoms in strawberry workers was explored. Second, we aimed to prove the concept that an IgE-mediated allergy could be responsible for work-related symptoms. To test the possibility of an IgE response secondary to cross-reactivity to birch or grass pollen, inhibition experiments were performed. Methods: First, a questionnaire survey concerning work-related allergic symptoms among strawberry workers in the Netherlands was carried out. Second, 3 workers with work-related symptoms were investigated in detail. Skin tests, serum-specific IgE tests with home-made extracts of strawberry pollen and other possible allergenic agents of the strawberry greenhouse environment were executed. Furthermore, immunoblots and nasal provocations with strawberry pollen extract were performed. In addition, inhibition experiments were performed. Results: 29 of 75 questionnaire respondents (38.7%) reported work-related symptoms. Sensitization to strawberry pollen was found in skin tests in all 3 employees with work-related symptoms. ELISA and immunoblotting with strawberry pollen showed positive results in 2 employees. Birch and grass pollen failed to inhibit IgE binding to strawberry pollen in 1 of 2 employees. Partial inhibition was seen in the second employee. Nasal provocation validated clinically relevant allergy to these pollens in 2 of 3 subjects. Conclusions: Allergic symptoms attributable to the workplace are present among a proportion of strawberry greenhouse employees. An IgE-mediated occupational allergy to strawberry pollen may contribute to these symptoms
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